From the factory, the XPS 15's QHD+ IGZO display is set to push color saturation to unnatural levels. This is easily fixed, thankfully.
Go to Windows Mobility Center and switch the color profile from "splendid mode" to "generic color".
Note that if you reinstalled Windows 8/8.1 from a plain Microsoft source rather than a Dell-customized source, you will need to install the Dell Quickset application for the Color Mode option to appear in Mobility Center. Quickset can be downloaded from the XPS 15 9530 Drivers page on support.dell.com and adds a few device-specific settings and on-screen overlays for keyboard buttons. It does not sit in your system tray or otherwise spam your interface as most OEM software tends to.
Additionally, it seems that customers running Windows 8.x that have received motherboard replacements have found that splendid mode is enabled after the replacement (even if it was disabled previously) and the option to manage it no longer appears in Windows Mobility Center. The fix seems to be to go into the BIOS and disable Secure Boot (this will automatically enable Legacy Option ROMs, which is what you want), then save changes and reboot. The splendid mode toggle should return. At this point you can go back into the BIOS and enable Secure Boot again (this forces Legacy Option ROMs off, which is fine and actually preferable for Windows 8.x) and you should still have splendid mode in Windows Mobility Center. It's unclear why a motherboard replacement causes the splendid mode option to disappear and why the permanent fix seems to be boot just once with that particular BIOS configuration, but this has been confirmed by two owners.